The invention relates to volume control, and more particularly to volume control regulated by a digitally adjustable resistor.
In an audio system playing an audible signal through a speaker, adjustments in volume typically may be made in an analog or a digital fashion. An analog volume control typically continuously changes the amplitude of the output signal, generally producing a smooth change in volume. A digital volume control typically changes volume in a series of one or more discrete steps, which may cause a step change in the output going to the speaker. This step change may produce an artifact that sounds like a xe2x80x9cpopxe2x80x9d or xe2x80x9cclickxe2x80x9d to the listener, with the level of the pop typically depending on the height of the step change of the output. A large step change typically causes a larger pop than a small step change. Pops that are easily audible are undesirable, and manufacturers of audio equipment often strive to minimize or eliminate these artifacts.
Moreover, recent audio standards have required the ability to adjust volumes over a very large range, e.g., 90 db. This means that the volume control may need to change volume levels over a very wide range. means that the volume control may need to change volume levels over a very wide range.
The device described herein provides volume transitions and with minimal incidental noise.
The invention provides a volume control device including a digitally adjustable resistor that can be selectively connected across any of a number of volume controlling resistors. The digitally adjustable resistor can be adjusted to allow a volume transition in a series of incremental steps of small magnitude. This incremental transition results in a smooth transition between volume levels, and minimizes incidental noise.